The development and characterisation of triglyceride-based 'spontaneous' multiple emulsions

The formation of multiple emulsion droplets from two oil systems (Labrafil M 1944 CS and Labrafac Lipophile WL 1349) via a one-step process involving minimal agitation in aqueous media has been investigated in terms of the multiple character of the droplets, the particle size distribution, the stability and the lipolysis profile in the presence of pancreatic lipase. It was noted that multiple emulsion droplets were formed from both oils in the presence and absence of Tween 80, with the stability and particle size of the droplets being dependent on the composition and choice of media. It was noted that optimum stability of up to several days was obtained using 10% Tween 80 for both oils, with two stages of the breakdown process being apparent, the relative propensities of which being dependent on the oil used. The particle size distribution in distilled water indicated the presence of two distinct size populations corresponding to multiple and single droplets. It was noted that droplet breakdown was greatly accelerated in simulated intestinal fluid and in high pH media, with evidence for liquid crystal structure formation apparent. Lipolysis studies indicated that pegylation and the presence of surfactant slowed the degradation process. The study has indicated that 'spontaneous' multiple emulsion formation is indeed possible, with a reasonable if not necessarily optimal stability profile being observed for these systems.